Power management for signage may take many forms in providing effective power control for illumination. Visible light from emitters typically will impinge on the surface of a reflective sign surface and then be radiated outwardly to perspective viewers of the signage. In the early stages of the development of highway signage, visible light emitters comprised a matrix of incandescent light bulbs, and the highway signage was controlled by electromechanical controllers. Those electromechanical controllers typically employed mechanical relays and switches to implement the various functions of the controller.
The use of solar energy as a power source for illumination of highway signage is more recent in the art field. A solar power source typically comprises a plurality of photovoltaic cells, operatively connected, to produce a voltage and transmit an electrical current. The solar power source combined with a rechargeable battery or batteries provide the power for a visible light emitting array both in day light and during night time. When the output voltage of the solar power source drops below a certain level after sunset, the battery or batteries will discharge providing power to the visible light emitters. When the output voltage of the photovoltaic solar cells increases above a certain level after sunrise, battery voltage discharge stops and the output of the photovoltaic solar cells charges the batteries. The solar cells typically provide power to the visible light emitters of the highway signage during day light periods.
Highway signage display apparatus such as traffic markers, delineators, and other safety devices may be used to delineate highway traffic lanes, pillars, posts, barricades, support columns, entry and exit ramps, and crash cushion bars only to name a few. These display apparatus typically use one set of display elements during daytime lighting conditions, usually flip-disks or other passive elements with light reflecting or fluorescent surfaces. Another set is used during night time lighting conditions and they are generally light emitting diodes (LEDs) or other active elements with light emitting capability. These display apparatus may also be use in conjunction with one another during the daylight hours to provide enhances readability of the highway signage.